1. Field of the Invention
The present invention relates to a pressure sensitive sensor for detecting whether external force is operated to a predetermined portion and a method of treating a terminal of a pressure sensitive sensor.
2. Description of Related Art
In a vehicle such as a wagon or a recreational vehicle, a sliding door is adopted which allows a user to slide a door panel in either a forward or rearward direction in order to open and close an ingress and egress opening. Further, there is also adopted an automatic slide door apparatus for sliding a door panel by drive force of driving means such as a motor.
Additionally, in an automatic slide door apparatus, there is a case of attaching a pressure sensitive sensor at an end portion of a door panel on a side of a sliding direction for detecting squeezing of a foreign matter when the door panel is slid in a direction of closing an ingress and egress opening. The pressure sensitive sensor is constructed by a constitution of detecting reactive press force from a foreign matter when the pressure sensitive sensor presses the foreign matter in accordance with sliding of the door panel.
As an example of a pressure sensitive sensor of this kind, there is constructed a constitution in which a plurality of pieces of electrode lines (wires) each formed in a shape of an elongated string are provided at inside of an outer skin portion in a hollow elongated shape extending in a longitudinal direction along a height direction of a door panel, the outer skin portion comprising an insulating material having a predetermined elasticity such as a rubber material or the like.
According to the pressure sensitive sensor having such a constitution, any of the plurality of pieces of electrode lines is bent in accordance with elastic deformation of the outer skin portion by reactive press force of a foreign matter to thereby bring the bent electrode line into contact with other electrode line. As a result of contact of the electrode lines in such a manner, operation of external force to the outer skin portion, that is, squeezing of the foreign matter can be detected by detecting an electric change of a current value of current flowing in an electric circuit including the pressure sensitive sensor or a resistance value of the circuit.
Meanwhile, the pressure sensitive sensor of this kind must be connected to a power source for flowing current to detecting means or the pressure sensitive sensor for detecting the change in the current value of current flowing to the electric circuit or the resistance value of the circuit. Therefore, the electrode line is electrically connected to a lead wire directly or indirectly connected to the detecting means or the power source in a state of extracting the electrode line from one end of the outer skin portion by a predetermined length.
Further, in order to ensure mechanical strength at a portion of connecting the lead wire and the electrode line and maintain electric connection at the connecting portion, for example, it is conceived to connect the lead wire and the electrode line on a support plate in a plate-like shape and mold the connecting portion and the support plate, together with an end portion of the outer skin portion, by a synthetic resin material.
Here, the above-described mold is normally formed by arranging the connecting portion, the support plate and the end portion of the outer skin portion at inside of a mold die and filling the synthetic resin material in the mold die by injection molding.
However, according to the injection molding method, injection pressure of the synthetic resin material is high and fluidity of the synthetic resin material is low even in a molten state. Therefore, when the synthetic resin material is filled in the mold die by injection molding, the synthetic resin material flowing in the mold die applies pressure on the connecting portion of the electrode line and the lead wire, as a result, there is a possibility of bringing about disconnection at the connecting portion. Further, when the molding is carried out by including also the end portion of the outer skin portion as mentioned above, there is a possibility of flowing the synthetic resin material from an opening formed at the end portion of the outer skin portion to an inner side of the outer skin portion by filling the synthetic resin material at high pressure.
It is an object of the present invention to provide a pressure sensitive sensor and a method of treating a terminal of a pressure sensitive sensor which do not bring about disconnection at portions of connecting electrodes to each other or electrodes to other conducting member such as a lead wire in forming a covering portion such as a mold, in consideration of the above-described fact.
In order to achieve the above-described object, according to a first aspect of the invention, there is provided a pressure sensitive sensor comprising a hollow outer skin portion elastically deformable by an external force from outside and having an insulating performance, a plurality of electrodes which are arranged to be opposed to each other via an air gap on an inner side of the outer skin portion and one-side ends of which are drawn out from an end portion of the outer skin portion, a support member provided on a side of the end portion of the outer skin portion for supporting the one-side ends of the plurality of electrodes drawn out from the end portion of the outer skin portion and electrically connecting the plurality of electrodes to each other or the plurality of electrodes to other conductive member, and a covering portion formed by a material including at least either one of a thermoplastic resin material molded by hot met molding and a photo-curing resin material cured by absorbing a light energy for sealing at least a portion of the support member and the one-sides of the electrodes in an embedded state.
According to the pressure sensitive sensor having the above-described constitution, when the outer skin portion is elastically deformed by operating the external force to the outer skin portion, at least one of the plurality of electrodes provided at inside of the outer skin portion is elastically deformed along with the outer skin portion.
Since the plurality of electrodes are provided via the air gap, the plurality of electrodes are normally separated from each other, however, the electrodes are conducted by deforming at least one electrode along with the outer skin portion to be proximate to and brought into contact with other electrode. By detecting such conducting of the electrodes by a change in a current value flowing in the electrodes or a change in an electric resistance value of an electric circuit constituted by including the electrodes, contact of the electrodes, that is, operation of the external force to the outer skin portion can be detected.
Meanwhile, the one-side ends of the electrodes drawn out from the end portion of the outer skin portion are supported by the support member and the electrodes are electrically connected to each other or the electrodes are electrically connected to other conducting member by the support member. When the electrodes are connected to other conducting member, for example, the electrodes are connected to power supplying means of a power source or the like or detecting means for detecting the change in the current value or the change in the electric resistance value of the electric circuit as mentioned above via the other conductive member.
Here, the support member and the one-side ends of the electrodes are sealed in the covering portion in the embedded state and therefore water or dust is prevented from adhering to portions of connecting the electrodes to each other or portions of connecting the electrodes to other conducting member supported by the support member. Further, since the support member and the one-side ends of the electrodes are embedded in the covering portion, the above-described connecting portion is supported not only by the support member but at a surrounding thereof by the covering portion, to thereby restrict deformation thereof. Thereby, disconnection of the above-described connecting portion caused by accidental external force (impact or the like) applied to the support member and a vicinity thereof is prevented.
Further, the covering portion of the pressure sensitive sensor based on the aspect is constituted by at least either one of the thermoplastic resin material molded by hot melt molding (hereinafter, referred to as xe2x80x9chot melt molding resin materialxe2x80x9d) and the photo-curing resin material cured by absorbing light energy.
Here, with regard to the hot melt molding resin material or the photo-curing resin material, molding pressure in molding is lower than molding pressure in molding by a general injection molding method or, in some cases, the molding pressure is not necessary. Therefore, a possibility of effecting adverse influence on respective portions of the electrodes or the support member as well as the above-described connecting portions by the molding pressure becomes extremely low and connection between the electrodes and connection between the electrodes and other conducting member at the connecting portions can reliably be maintained.
According to a second aspect of the invention, the end portion of the outer skin portion of the pressure sensitive sensor is embedded in the covering portion to seal.
According to the pressure sensitive sensor having the above-described constitution, not only the support member and the one-side ends of the electrodes but also the end portion of the outer skin portion are embedded in the covering portion to seal. Thereby, invasion of water or invasion of dust or the like from the end portion of the outer skin portion is prevented.
Here, as described above, according to the hot melt molding resin material or the photo-curing resin material, the molding pressure is low or the molding pressure per se is not necessary and therefore, in molding the covering portion, flowing of the synthetic resin material from the end portion of the outer skin portion is prevented or alleviated. Thereby, it can be prevented to accidentally or unpreparedly flow a large amount of the synthetic resin material to the outer skin portion in forming the covering portion and nondetection of external force caused by such flowing of the synthetic resin material to cure can be prevented.
According to a third aspect of the invention, the covering portion of the pressure sensitive sensor includes an inner layer formed by the thermoplastic resin material molded by the hot melt molding or the photo-curing resin material for sealing at least a portion of the support member and the one-side ends of the electrodes in the embedded state, and an outer layer formed by the thermoplastic resin material molded by the hot melt molding or the photo-curing resin material integrally with the inner layer for covering at least a portion of the inner layer from an outer side and having a rigidity higher than a rigidity of the inner layer in a cured state.
According to the pressure sensitive sensor having the above-described constitution, at least a portion of the support member and one-side ends of the electrodes are sealed in the inner layer in the embedded state by the inner layer constituting the covering portion, further, at least a portion of the inner layer is covered by the outer layer integrally provided with the inner layer on the outer side.
Here, the inner layer and the outer layer are formed by the hot melt molding resin material or the hot-curing resin material. However, the rigidity of the synthetic resin material forming the outer layer in the cured state is higher than the rigidity of the synthetic resin material forming the inner layer in the cured state.
The outer layer having the rigidity higher than that of the inner layer ensures strength against unprepared external force (for example, impact) and maintains its shape against such an external force (that is, deformation of the outer layer by external force is smaller than that of the inner layer). Thereby, disconnection of portions of connecting the electrodes to each other or portions of connecting the electrodes to other conducting member caused by deforming the covering portion by unprepared external force can be prevented over a long period of time.
Meanwhile, the inner layer having the rigidity lower than that of the outer layer (in other words, having high elasticity) holds the portions of connecting the electrodes to each other or the portions of connecting the electrodes to other conducting member in the support portion comparatively flexibly. Further, when the above-described unprepared external force is assumedly exerted to the outer layer, external force transmitted to the inner layer via the outer layer is absorbed by the inner layer by elasticity of its own. Also thereby, disconnection of portions of connecting the electrodes to each other or the portions of connecting the electrodes to other conducting member caused by deformation at the covering portion by unprepared external force can be prevented over a long period of time.
Further, as combinations of synthetic resin materials for forming respectives of the inner layer and the outer layer, there can be four kinds of a constitution: a constitution of forming the inner layer by the hot melt molding resin material and forming the outer layer by the photo-curing resin material; a constitution of forming the inner layer by the photo-curing resin material and forming the outer layer by the hot melt molding resin material; a constitution of forming the inner layer and the outer layer by the hot melt molding resin material; and a constitution of forming the inner layer and the outer layer by the photo-curing resin material. However, the combination may be any of the four kinds of constitutions.
According to a fourth aspect of the invention, the covering portion of the pressure sensitive sensor is made transparent or semitransparent.
According to the pressure sensitive sensor having the above-described constitution, the covering portion is transparent or semitransparent and therefore, connection of the electrodes and connection of the electrodes to other conducting member can be confirmed without detaching the covering portion or destructing the covering portion. Thereby, acceptability determination in an inspecting step after forming the covering portion or in maintenance is facilitated and operational efficiency is promoted.
According to a fifth aspect of the invention, the covering portion includes an engaging portion provided integrally therewith and the covering portion and the outer skin portion are integrally held via the engaging portion.
According to the pressure sensitive sensor having the above-described constitution, by directly or indirectly engaging the engaging portion integrally provided with the covering portion to the outer skin portion at a predetermined attached portion, the covering portion can be held at the attached portion via the engaging portion. Thereby, at least a portion of the pressure sensitive sensor can be fixed at the attached portion and therefore, external force at the attached portion can be detected.
According to the pressure sensitive sensor, as described above, at least the covering portion is firmly held at the attached portion. Therefore, even when vibration or the like is brought about at the outer skin portion, vibration or the like at the covering portion is alleviated or prevented. Thereby, disconnection of connection between the electrodes and connection between the electrodes to other conducting member in the covering portion caused by vibration or the like can be prevented.
According to a sixth aspect of the invention, the engaging portion of the pressure sensitive sensor is formed by a material the same as a material of the covering portion.
According to the pressure sensitive sensor having the above-described constitution, the engaging portion engaged directly or indirectly with the attached portion and held at the attached portion is formed by a material the same as that of the covering portion, that is, the photo-curing resin or the hot melt molding resin material. Therefore, by forming the covering portion, the engaging portion is formed along with the covering portion. Thereby, a member of separately constituting the engaging portion is not necessary. As a result, a reduction in a number of parts and a reduction in integrating steps can be achieved, which significantly contributes to a reduction in cost.
According to a seventh aspect of the invention, there is provided a method of treating a terminal of a pressure sensitive sensor for treating the one-side ends of the plurality of electrodes drawn out from the end portion of the outer skin portion when the pressure-sensitive sensor according to the first aspect is produced, the method comprising (a) a connecting step of making the support member support the one-side ends of the plurality of electrodes and electrically connecting the electrodes to each other or the electrodes to other conductive member, (b) an inner layer molding step of forming an inner layer constituting the covering portion by arranging at least a portion of the support member and the one-side ends of the electrodes in an inner layer molding die and filling a photo-curing resin material cured by absorbing a light energy or a thermoplastic resin material molded by hot melt molding in the inner layer molding die so that at least the portion of the support member and the one-side ends of the electrodes are embedded in the inner layer to seal, and (c) an outer layer molding step of forming an outer layer constituting the covering portion by arranging at least a portion of the inner layer in an outer layer molding die and filling a photo-curing resin material cured by a rigidity higher than a rigidity of the inner layer by absorbing the light energy, or a thermoplastic resin material molded by the hot melt molding and having a rigidity higher than the rigidity of the inner layer in a cured state, in the outer layer molding die, so that at least the portion of the inner layer is covered by the outer layer.
According to the method of treating the terminal of the pressure sensitive sensor having the above-described constitution, first, in the connecting step, the one-side ends of the plurality of electrodes drawn out from the end portion of the outer skin portion are supported by the support member and the electrodes are electrically connected to each other or the electrodes are electrically connected to other conducting member.
Successively, in the inner layer molding step, at least the portion of the support member and the one-side ends of the electrodes are arranged in the inner layer molding die and under the state, the thermoplastic resin material molded by hot melt molding (hereinafter, simply referred to as xe2x80x9chot melt molding resin materialxe2x80x9d) or the photo-curing resin material cured by absorbing light energy is filled in the inner layer molding die.
Under the state, the inner layer constituting the covering portion is formed by curing the synthetic resin material (hot melt molding resin material or photo-curing resin material) filled in the inner layer molding die and at least the portion of the support member and the one-side ends of the electrodes as well as the portions of connecting the electrodes to each other or the portions of connecting the electrodes to other conducting member are sealed in the inner layer in the embedded state.
Here, in comparison with the case of molding the inner layer by a general injection molding method, in the present method of utilizing the hot melt molding resin material or the photo-curing resin material, molding pressure in molding is low or molding pressure per se is not necessary. Therefore, the hot melt molding resin material or the photo-curing resin material filled in the inner layer molding die does not press the support member or the electrodes by large force. Thereby, the support member and the electrodes are reliably disposed at previously set predetermined positions in the inner layer.
Further, since as described above, the hot melt molding resin material or the photo-curing resin material does not press the support member or the electrodes by large force, the photo-curing resin material does not disconnect the portions of connecting the electrodes to each other and the portions of connecting the electrodes to other conducting member and thus connection at the above-described connecting portions can firmly be maintained.
Furthermore, in comparison with a case of molding by a general injection molding method, the hot melt molding resin material or the photo-curing resin material is cured in a short period of time. Therefore, by using the hot melt molding resin material or the photo-curing resin material, the inner layer is formed in a short period of time and a number of operating steps can significantly be reduced.
Next, when the inner layer has been formed as described above, in the outer layer molding step, at least a portion of the previously formed inner layer is arranged in the outer layer molding die. Under the state, the hot melt molding resin material or the photo-curing resin material is filled in the outer layer molding die. By curing the hot melt molding resin material or the photo-curing resin material filled in the outer layer molding die, a portion of the inner layer arranged in the outer layer molding die is covered by the outer layer.
As described above, in the hot melt molding resin material or the photo-curing resin material, molding pressure in molding is low or molding pressure per se is not necessary and therefore, the outer layer is formed in a short period of time and a number of operating steps can significantly be reduced.
Meanwhile, according to the invention, the rigidity after curing of the synthetic resin material (that is, hot melt molding resin material or photo-curing resin material) for forming the outer layer is larger than that of the synthetic resin material (that is, hot melt molding resin material or photo-curing rein material) for forming the inner layer.
Therefore, the outer layer ensures strength against unprepared external force (for example, impact) and maintains its shape against such an external force (that is, deformation of the outer layer by external force is smaller than that of the inner layer). Thereby, disconnection of portions of connecting the electrodes to each other or portions of connecting the electrodes to other conducting member caused by deformation at the covering portion by unprepared external force can be prevented over a long period of time.
Meanwhile, the inner layer having the rigidity lower than that of the outer layer (in other words, having high elasticity) holds the portions of connecting the electrodes to each other or the portions of connecting the electrodes to other conducting member in the support member comparatively flexibly. Further, when the above-described unprepared external force is assumedly exerted to the outer layer, external force transmitted to the inner layer via the outer layer is absorbed by the inner layer by elasticity of its own. Also thereby, disconnection of the portions of connecting the electrodes to each other or the portions of connecting the electrodes to other conducting member caused by deformation at the covering portion by unprepared external force can be prevented over a long period of time.
Further, as combinations of synthetic resin materials for forming respectives of the inner layer and the outer layer, there can be four kinds of a constitution: a constitution of forming the inner layer by the hot melt molding resin material and forming the outer layer by the photo-curing resin material; a constitution of forming the inner layer by the photo-curing resin material and forming the outer layer by the hot melt molding resin material; a constitution of forming the inner layer and the outer layer by the hot melt molding resin material; and a constitution of forming the inner layer and the outer layer by the photo-curing resin material. However, the combination may be any of the four kinds of constitutions.
According to an eighth aspect of the invention, the (b) inner layer molding step further includes a step of arranging the end portion of the outer skin portion in the inner layer molding die.
According to the aspect, in the inner layer molding step of the method of treating the terminal of the pressure sensitive sensor, the end portion of the outer skin portion is arranged in the inner layer molding die. Therefore, the end portion of the outer skin portion is embedded in the inner layer.
Thereby, invasion of water or invasion of dust or the like from the end portion of the outer skin portion can be prevented.
Here, as described above, in molding the hot melt molding resin material or the photo-curing resin material constituting the inner layer, molding pressure is lower than that of a general injection molding method or molding pressure per se is not necessary and therefore, when the hot melt molding resin material or the photo-curing resin material is filled in the inner layer molding die, flowing of the synthetic resin material (hot melt molding resin material or photo-curing resin material) from the end portion of the outer skin portion can be prevented or alleviated. Thereby, nondetection of external force by the pressure sensitive sensor caused by such flowing of a large amount of the synthetic resin material to cure can be prevented.
According to a ninth aspect of the invention, at least either one of the (c) outer layer molding step and the (b) inner layer moldering step, further includes (d) a step of forming an engaging portion integral with the covering portion, and (e) a step of holding the covering portion and the outer skin portion in air tight and integrally via the engaging portion.
According to the aspect, in either one of the outer layer molding step and the inner layer molding step, when the synthetic resin material in correspondence with the step is filled to the corresponding molding die, the engaging portion is formed along with the covering portion constituted by the inner layer and the outer layer. When the pressure sensitive sensor is attached to a predetermined attached portion, by engaging the engaging portion to the attached portion, the covering portion is held at the attached portion via the engaging portion.
That is, also the engaging portion is formed simultaneously with the covering portion and therefore, a member or a step of particularly constituting the engaging portion is dispensed with. Thereby, cost can be reduced considerably.